Fuse link construction



Jan. 13, 1942.

A. G. STEINMAYER FUSE LINK CONSTRUCTION original Filed Nov. 16, 1934yOlm Patented Jan. 13, 1942 Emst/63270225 UNITED STATES PATENT OFFICE yFUSE LINK CONSTRUCTION Alwin G. Steinmayer, South Milwaukee, Wis., as-

signor to Line Material Company, South Milwaukee, Wis., a corporation ofDelaware Original application November 16, 1934, Serial No.

Divided and this application November 24, 1941, Serial No. 420,295

39 Claims. (Cl. 20o-117) This invention relates to improvements intension type fuse links.

The subject matter hereof has been divided from my copending applicationSerial No. 753,358,

filed November 16, 1934, pursuant to Patent Ofan expulsion fuse tube,whereby the tension of the fuse link may be set at a standard valueprior to its incorporation into a fuse tube.

Another object is to provide a factory tensioned fuse link forreplacement in an expulsion tube which will be expelled from the tube bythe tensioning spring when the fusible section of the fuse link issevered.

A still further object is to provide a factory tensioned fuse link inwhich the fuse link is provided with means for -guiding the spring whichtensions the fusible section of the link.

It is also a further object, to provide a fuse link having a tensionedfusible section and a. rigid section expellable from an expulsion fusecartridge by means of the tension spring when the fusible section issevered, the rigid section serving as a guide to the spring andmaintaining its direction of movement from the cartridge substantiallyunchanged and thereby compelling the flexible portionof the link to movefrom the cartridge.

It is still another object to provide an elongated rigid section whichmay be actuated, when the fusible section of the link is severed, to avelocity greater than would be possible with the ilexible'section alone.

It is also another object to provide a flexible fuse link with a portionadjacent the fusible section and which is less fusible than the flexibleportion of the link, thereby keeping the metallic gases generated by thearcv at a minimum and consequently shortening the time during whichthelarc will continue.

It also is an object to provide an assembled tensioned fuse link incombination with an arc suppressing material which will destroy or in'terrupt an arc created after the fusible sections of the link have beenseparated.

In the drawing:

Figure l is a view in side elevation of a fuse.

tube with a portion broken away to show a fuse link embodying thisinvention mounted therein.

Figure 2 is a view in side elevation of the fuse link shownv in Figure 1and embodying this in vention, portions being broken away to show theinner elements.

Figure 3 is a view similar to Figure y2 showing a further modified form.

Figure 4 is a view in vertical section showing a tensioned and arcextinguishing fuse link embodying this invention.

Throughout the several views, like parts are referred to by the samereference characters.

The expulsion fuse cartridge shown in Figure l comprises an electricallynon-conductive tube I, an upper tubular g contact terminal 2 to whichthe tube I is threaded, a closure cap 3 threaded to the terminal 2, anda lower contact terminal 4 through which the tube I extends and to which,it is secured. The lower contact is provided with a link engagingclamping bolt 5 threaded into the boss 6 on the terminal l. This boss isslotted transversely relative to the bolt 5 to receive the flexible endof the fuse link, as will more particularly be described hereafter.

'I'he fuse link shown in Figures l and 2 comprises an upper contact capI seated on the upper terminal 2 and connected by the portion l to thestrip 9 which is notched at I0 to provide an area that may be easilysevered to adapt it for insertion in other types of fuse tubes than thatshown. The strip 9 is secured by means of solder I I to a strain wireI-2 having a high melting point and to a` fuse wire I3 having a low`melting point. Both of these wires I2 and I3 are secured by solder Ilto the flexible wire 2I,

as shown in Figure 2.

As illustrated in Figure 2, the stripy 8 has an area I1 reduced in widthto be received in the .insulating tube I8 which surrounds the strainwire I2, fusible wire I3, and flexible wire 2 I. In Figures l. and 2, acoil spring l5 engages the lower end of the tube I8 by means of a nutwasher 3l threaded on the spring and is coaxial with the flexible wire2I. The upper end of the spring 35 is crimped into engagement with theupper end of the flexible wire 2| to exert a pull on the strain wire I2,thus maintaining the strain wire under tension. The flexible wire 2Iextends to the lower opening of the tube I and is bent back upon theouter side of the tube to position the end 23 in the slotted lug 5 onlower contact terminal 4 to be clamped by means of the clamping bolt 5.

lIn Figure 3, the rod I5 is secured in any suitable manner (such assoldering) at 33 to the flexible wire 34. A tube Il surrounds the rod Iand spring 35 which is coaxial with the rod and is engaged with theupper end thereof at 35. Seated on the lower' end of the tube is a nutwasher 31 threaded on the lower end of the spring and holding the springunder tension. The arrangement of the elements in Figure 3 is the sameas that in Figure 2, except that the rod I5 in Figure 3 is substitutedfor that portion oi the flexible wire 2| which extends into the tube I3in Figure 2. y

Figure 4 illustrates the invention disclosed in Figures 1 to 3inclusive. The fuse link comprises a contact cap 45, a fusible section46 secured to the cap and to the rod 49. Surrounding the fusible sectionis a compound of arc extinguishing material 48 which is enclosed by theinsulating tube 50. A cap or plug 5| closes the bottom of the tube andserves as a seat for the spring 52 and is centrally apertured to receivethe rod 49. The plug 5I also serves to retain the material 43 in thetube if such material is made in powder form. In this form of theinvention, the insulating tube 50, cap 45, and plug 5I will conne thearc extinguishing material. The spring 52 is held under compressionbetween the plug 5I and washer 53 by means of the wire 46 and rod 43 towhich the washer 53 issecured by soldering. The rod 49 is likewisesecured to the flexible section 54 of the fuse link.

From the foregoing description, it will be observed that each of theembodiments of the invention disclosed herein is provided with guidingmeans for the fuse tensioning springs. In Figures 3 and 4, the guidingmeans comprises, respectively, the rod I5 in Figure 3 and the rod-43 inFigure 4. In Figure 4, the spring 52 is under compression, and thereforethe rod 49 holds the spring from lateral movement intermediate the ends.In Figure 3, the spring 35 is elongated so that it is pulling on theupper end of the rod I5. In this latter form, the spring naturally willtend to remain coaxial with the spring link. However, when the fuse wireI3 and tension wire I2 are severed, the spring impels the rod I5 towardthe lower end of the tube I8. If the rod I5 is not provided, there wouldbe some tendency for the spring to jam within the walls of the tube I3,although this would not be a serious matter in a carefully constructed-fuse link such as shown in Figure 3. As a matter of fact, the tube Ilitself will produce to a considerable extent In Figure 2, I have notillustrated guiding means constituting a portion of the fuse linkproper. However, I have shown the tension springs disposed in the tubesenclosing the fusible sections of the fuse links. tube surrounding thespring acts as the guide for the spring and holds the spring throughoutits length substantially coaxial with the fuse link.

When the fuse wire I3 and tension wire I2 are severed, the spring willcause the link to move relatively downward with respect to the tubes andtoward the open end of the cartridge I. The impetus attained through theaction of the spring will be manifested in a very high velocity of thesevered end of the link toward the open end of the fuse cartridge I.Even after the spring has spent its energy, the kinetic energy of motionof the fuse link will cause the link to continue its movement until ithas been expelled from the fuse cartridge.

the foregoing noted results produced by the rod l' The portion of thelThus, it will be seen that a fuse link has been provided in which thetension exerted on the fusible section may be set at a predeterminedvalue prior to its insertion in a fuse cartridge and in which theexpulsion action is positive and not dependent upon any possibleexpelling effect that may arise from the arc. As a matter of fact, thetendency is to extinguish the arc much quicker than it would ordinarliybe extinguished in a non-tensioned fuse link.

The operation of the device shown in Figure 4, when expelling the fuselink from a fuse cartridge, is substantially like the action of thedevice illustrated in Figure 2. However, there is an added feature tothe form illustrated in Figure 4 which embodies a material surroundingthe fusible section of the fuse link and which contains material fromwhich water vapor or other arc extinguishing gases may be evolved underthe iniiuence of an arc to impose in the path of the arc the equivalentof a resistance to the ilow of current. I prefer materials such as boricacid which give off water vapor under the influence of the heat of anarc Ifor the reason that it has been found that water vapor is extremelyeffective in extinguishing an arc. Thus, it will be seen that in theform illustrated in Figure 4, I obtain a separation of the fuse sectionsin a minimum space of time and also secure the extinguishing of the arcmuch sooner than it would be extinguished without the evolution of watervapor. While I have stated that I prefer material such as 'boric acid,it will be understood that I may use other materials which will evolveeither water vapor or gases such as hydrogen which will effectivelydestroy an arc.

It will be noted that in the structure illustrated in Figure 4 thematerial 48 provides the equivalent of a small bore of substantially thesame size as and enclosing the fusible section 45 of the link. Theeffect produced by this small bore upon an arc is to confine the arc toa limited space and consequently greatly increase the resistance to flowof current through the bore when the fusible section has separated.While I have indicated that I prefer boric acid as an arc extinguisher,it will be obvious from the foregoing that a sleeve of electricallynon-conductive material, such as rotten stone, maybe used for the solepurpose of restricting the arc path and thereby suppress the arc soonerthan the arc would normally be suppressed if the sleeve is not provided.There conceivably are conditions under which a restricted path willserve to suppress an arc justas satisfactorily as water vapor or otheruids. For this reason, I do not restrict all of the claims to the use ofboric acid or other volatilizable material. Figure 4 illustrates a novelmethod of suppressing an arc at the same time that the fused sections ofthe link are being separated by the spring. Therefore, claims predicatedupon the invention disclosed in Figure 4 are intended to cover anyequivalent arrangement producing the same results.

When this invention is used without arc suppressing material, I preferthe arrangement shown in Figure 3 or its equivalent. In the linksillustrated in Figures 3 and `4, I; have provideda rod section I5 and49, respectively, each provided with an expulsion spring concentrictherewith.

In the Figure 3 link, the spring 35 is under tension, while in theFigure 4 link, the spring is under compression.

One of the advantages of having a portion of the link constructed -of asolid rod is ln the fact that the possibility' of the metal beingvaporlzed by the arc between separated portions of the link is reducedto a minimum. It has been found that the fine strands of a flexibleconductor will heat more readily and accordingly vaporize more freelythan a single large conductor, such as illustrated in Figures 3 and 4.Therefore, it is desirable to place a single solid conductor in the linkbetween the flexible section and the fusible section. vThe solidconductor spaces the flexible section of thelink from the fusiblesection and prevents the arc from reaching the more easily fusiblestrands of the flexible section.

A further function of the rods l5 and 49 is to serve as means to which ahigh velocity may be positively and quickly imparted and which will tendto maintain a substantially straight line movement after motion has beenimparted thereto by their respective springs. In those modifications offuse links which are not provided with rod or rigid conducting section,the flexible portion of the fuse link tends to interfere with thesprings when the latter are relieved of their tension. While I haveindicated that the use of a rigid vsection in the fuse link isdesirable, nevertheless, those fuse links which are not provided withrigid sections in the link give satisfactory service, because I haveprovided a rigid member in the form of an insulating tube which guidesthe spring and the flexible section of the link and thereby assists thespring in imparting a maxlmum velocity to the link in the quickestpossible time. The rod section of the link gives the added feature ofprotecting the flexible section against fusion.

I claim:

1. A fuse link comprising a pair of terminals, a fusible sectionconnecting the terminals, a sleeve of insulation surrounding the fusiblesection and carried on the link, ra strain element connected between theterminals and lying within the sleeve and wholly out of contact with thefusible section, and a spring carried by the link,

said spring being under stress tending Vto separate said terminals.

2. A renewable fuse link comprising, a fuse tube, a relatively infusibleterminal at one end of said fuse tube, a conductor including a flexiblelead extending out of the other end of said fuse tube, a strain wireinterconnecting said terminal and said conductor, a fusible elementinterconnecting said terminal and said conductor, said fusible elementbeing in the form of a wire 'the length of which betweensaid terminaland s.'

said conductor is-substantially greater than th'e distance therebetween,and a spring reacting .against said fuse tube and tensioning said strainwire.

3. A fuse link including a fusible section, a

relatively rigid section, and a flexible' section' electricallyconnected by said rigid section to said fusible section; in combinationwith a spring concentric with said rigid section and comprising noportion of the circuit through said link, said spring being connectedatone end with the fusible section and having its tension exerted betweenthe ends of the fusible section, and an insulating member interposedbetween the other end of said spring and said link, whereby said springis held under tension.

4. A fuse link including a fusible'section, a relatively rigid section,and a flexible section electrically connected by said rigid section tosaid fusible section; in combination with a spring con- 75 washerthreaded on the tube engaging end of` centrically related thereto andcomprising no portion of the circuit through said link, a tubesurrounding the fusible section, and means engaging one end of said tubewith the corresponding end of said fusible section, said spring beingheld under tension by a portion of the link intermediate the ends ofsaid tube and by the end of said tube remote from said fusible section.

i 5. A fuse link comprising a terminal portion, a fusible section, aflexible section, an insulating tube surrounding the fusible section,said tube being engaged with the terminal portion, a helical springconcentrically related to said flexible section and including meansconnecting one end of said spring and the flexible section, the otherend of said spring engaging the tube at a point remote from the terminalportion thereby to tension the fusible section, and an arc suppressingmaterial in said tube.

6. A fuse link comprising a terminal portion, a fusible section, aflexible section, an insulating tube surrounding the fusible section,said tube being engaged with the terminal portion, a helical springconcentrically related to said flexible section and including meansconnecting one end of said spring and the flexible section, the otherend of said spring engaging the tube ata point remote from the terminalportion thereby to tension the fusible section, and a deliquescentmaterial in said tube whereby arc suppressing material will begeneratedwhen the fusible section is severed.

'7. A fuse link having. a terminal section, a separable section, a rigidsection, and a. flexible section, in combination with an insulating tubeengaged with the terminal section and surrounding the fusible sectionand at least a portion of the rigid section, and a spring surroundingthe rigid section and having one end engaged with the tube remote fromthe terminal section and the other end engaged with the rigid section,said flexible section being wholly exterior of said tube.

8. A fuse link having a terminal "section, a separable section, a rigidsection, and a flexible section, in combination with an insulating tubeengaged with the terminal section and surrounding the fusible sectionand at least a portion of thelrigid section, a spring surrounding therigid section and having one end engaged with the tube remote from theterminal section and the other end engaged with the rigid section, andan arc suppressing material in the tube.

9. A fuse link having a terminal section, a separable section, a rigidsection, and aflexible section, in combination with an insulating tubeengaged with the terminal section and surrounding the fusible sectionand at least a portion of the rigid section, a spring surrounding therigid section and having one end engaged with the tube remote from theterminal section and the other end engaged with the rigid section, andanarc extinguishing material in the tube, said arc extinguishing materialembodying water of crystallization.

10. A fuse link including a terminal section, a fusible section, aflexible section, and tensioning means for the fusible section: saidmeans comprising a spring connected at oneI end with the flexiblesection, a. tube interposed between the other end of the spring and theterminal section whereby to hold said spring under stress andsurrounding the fusible section and at least a ,portion of said spring,and a tube engaging the spring and reciprocal relative to said flexiblesection.

11. A fuse link comprising a terminal, a fusible section connected tothe terminal, a rigid section connected to the fusible section, aflexible section electrically connected With the rigid section, a tubesurrounding said fusible section and a portion of said rigid section andengaged with said-terminal, and a spring concentric with the tube andengaged at one end therewith, the other end of the spring being engagedwith said rigid section at a point remote from the tube, therebytensioning said fusible section.

l2. A fuse link comprising a terminal, a fusible section secured to theterminal, a rigid section secured to the fusible section, a tensioningtube engaged with said terminal and enclosing said fusible section, aspring concentric with the rigid section disposed in said tube andengaged with the rigid section and the tensioning tube.

13. A tubular insulating member, contact means closing one end of saidmember, said member being open at the other end, a contact on saidmember intermediate the ends thereof, a conductor in said memberconnecting said contacts, said conductor having a separable portion insaid member and a flexible conducting portion extending from theseparable portion and from the open end of said member, a tube and aspring, said tube being engaged at one end with said conductor and at aportion remote therefrom with said spring, said spring being engagedwith said conductor, whereby to tension said separable portion.

14. The combination with a fuse tube having upper and lower contacts andopen at one end, of a fuse link comprising a terminal engaged with theupper contact, a fusible section connected to the terminal, a rigidsection connected to the fusible section, a flexible sectionelectrically connected with the rigid section, a second tube surroundingsaid fusible section and a portion of said rigid section and engagedwith said terminal, and a spring concentric with the second tube andengaged at one end therewith, the other end of the spring being engagedwith said rigid section at a point remote from the second tube, therebytensioning said fusible section.

l5. The combination with a fuse tube closed at one end by a contact andopen at the other end, of a fuse link in said tube, said fuse linkcomprising a terminal secured to said contact, a fusible section securedto the terminal, a rigid section secured to the fusible section, atensioning tube within the first mentioned tube engaged with saidterminal and enclosing said fusible section, a spring concentric withthe rigid section disposed in said tube and engaged with the rigidsection and the tensioning tube.

16. A tubular insulating member, contacts on said tube in spacedrelation to each other, a conductor in said member connecting saidcontacts, said conductor having a separable portion in said member, anda flexible portion, an insulating tube surrounding the separableportion, i

and a spring tensioning said separable portion and disposed whollywithin said member, said tube and spring being engaged with each otherand with portions of said conductor to tension said separable portion.

17. A tubular insulating member, contact means closing one end of saidmember, said member being open at the other end, a contact on saidmember intermediate the ends thereof, a conductor in said memberconnecting said contacts, said conductor having a separable portion insaid member and a flexible conducting portion extending from theseparable portion. a tube and a spring, said tube being engaged at oneend with said conductor and at a portion remote therefrom with saidspring, said spring being engaged with said conductor, whereby totension said separable portion.

18. A fuse link comprising a terminal section, a fusible section, ailexible section, and a rigid section connecting the fusible section andthe flexible section; in combination with a tube engaging lthe terminalsection and surrounding the fusible section and a portion of the rigidsection, and a spring engaged at one end with the rigid section and atthe other end with the tube, whereby to tension the fusible section.

19. An electrically conducting link including a separable section, aflexible section, and a rigid section connecting the separable sectionand the flexible section: in combination with a tube surrounding theseparable section and a portion of the rigid section, and a springengaged with the tube at the end remote from the separable section andwith the rigid section at a point remote from the tube.

20. A fuse link for expulsion cartridges, said link including a fusiblesection and a flexible section electrically connected to said fusiblesection; in combination with a spring concentrically re lated theretoand comprising no portion of the circuit through said link, a tubesurrounding the fusible section, and means engaging one end of said tubewith one end of said fusible section, a portion of the link intermediatethe ends of said tube being held under tension by said spring and by theend of said tube remote from said fusible section, said flexible sectionextending from said remote end to provide a terminal adapted to extendto the exterior of a cartridge.

2l. A unitary embodiment of a replaceable spring tensioned fuse link forfuse cartridges, said link comprising a terminal portion, a fusible section, and a exible section, all electrically connected in series and incombinationwith an in sulating tube engaging the terminal portion andsurrounding the fusible section and a portion of said flexible section,said flexible section extending from said tube and being adapted toextend to the exterior of a cartridge, and a spring in said tube havingmeans engaging one end thereof with the end of the tube remote from saidterminal portion, the other end of said spring being engaged with saidlink at a point intermediate the ends of said tube, said tube holdingsaid spring under tension, whereby said fusible section is placed undertension prior to insertion into a fuse cartridge.

22. A unitary embodiment of a replaceable spring tensioned fuse link forexpulsion fuse cartridges, said link comprising a terminal porv tion, afusible portion, a relatively rigid portion. and a iiexible portion` allelectrically connected in series and in combination with an insulatingtube engaging said terminal portion and concentrically related to saidfusible portion and said rigidy portion, and a spring held under stressbetween said rigid portion and said tube, whereby said fusible portionis tensioned, the tension on said fusible portion being predeterminedbefore said fuse link is placed in a fuse cartridge, said flexibleportion extending from said rigid portion exteriorly of said tube andadapted for extension to the exterior of a cartridge.

23. A unitary fuse link for insertion into standard expulsion fusecartridges of varying lengths and bores having upper and lower lineterminals and open at its lower end, said link comprising a fusibleportion, a flexible terminal portion electrically connected with one endof said fusible portion and of a length permitting said flexible portionto extend out from the open end of said expulsion fuse cartridge forconnection with the lower line terminal, a secondl terminal engagingportion electrically connected with the opposite end of said fusibleportion for connection with the upper line terminal, a tubular membersurrounding said fusible portion, means retaining said tubular member inplace around said fusible portion prior to rupture thereof, and meansapplying a tension force to said fusible portion as the parts of saidlink are assembled into a unitary structure, whereby a quick separationof the fused portion will be obtained when the fuse is blown. 24.Aunitary fuse link for insertion into standard expulsion fuse cartridgesof varying lengths and bores having upper and lower line terminals andopen at its lower end, vsaid link comprising a fusible portion, aflexible terminal portion electrically connected with one end of saidfusible portion and of a length permitting said flexible portion toextend out from the open end of said `expulsion fuse cartridge forconnection with the lower line terminal, a second terminal engagingportion electrically connected with the opposite end of said fusibleportion forconnection with the upper line terminal, a tubular membersurrounding said fusible portion, means retaining said tubular'memberin'place around said fusible portion prior to rupture thereof, and meansapplying tension to said fusible portion and placing said tubularportion under compression as the component parts of said link are beingassembled to form a unitary fuse link.

25. A unitary fuse link for insertion into standard expulsion fusecartridges of varying lengths andbores having upper and' lower lineterminals and open at its lower' end, said link comprising a fusibleportion, a flexible terminal portion elec- 4.

trically connected with one end of said fusible portion and of a lengthpermitting said `flexible portion to extend out from the open end ofsaid expulsion fuse cartridge for connection with the lower lineterminal, a second terminal engaging portion electrically connected withthe opposite end of said fusible portion for connection with the upperline terminal, a tubular member surrounding said fusible portion, meansretaining said tubular member in place around said fusible portion priorto rupture thereof, and a coil spring coaxial with said tubular memberand co-acting therewith and with said terminal engaging portions toapply a predetermined tension to said 'fusible portion and a compressingforce upon said tubular member as the component parts of said link areassembled t6 form a unitary fuse link.

26. A unitary fuse link for insertion into standard expulsion fusecartridges of varying lengths and bores having upper and lower lineterminals and open at its lower end, said link comprising afusibleportion, a flexible terminal portion elec- ,trically connectedwith one end of said fusible portion and of a length permitting saidflexible portion to extend out from the open end of said expulsion fusecartridge forccnnection with the4V lower line terminal, a secondAterminal engaging portion electrically connected with the opposite en dof `said fusible portion for connection with the upper line terminal, atubular member surrounding said fusible portion, means retaining saidtubular member in place around said fusible portion prior to rupturethereof, said means comprising a coil spring, a bearing surface uponsaid second terminal engaging portion for contacting one end of saidtubular member, and means coacting with the opposite end portion of saidtubular member, whereby a predetermined tension force is'applied by saidspring to said fusible portion to insure a quick wide separation of itsparts upon rupture thereof, said tubular member acting as a compressionmember resisting tension force prior to rupture of said fusible portion.

27. As a new article of manufacture a spring tensioned fuse link adaptedfor insertion into standard expulsion fuse cartridges of varying lengthsand bores, said tension being predetermined When the component parts ofthe link are assembled prior to insertion into said cartridge, said fuselink comprising a fusible section, a flexible conducting leader composedof a relatively large number of `fine wires in parallel electricalconducting relation, means electrically connecting the fusible sectionand the flexible conducting leader and comprising a section which isless readily fusible than the fusible section and the flexibleconducting leader, a tube surrounding the fusible section, and a springheld under tension between said tube and fuse link, at least a portionof said flexible section being disposed exteriorly of said tube wherebyto prevent fusing of the flexible conducting leader when tne fusiblesection has blown.

28.' As a new article of manufacture a spring tensioned fuse linkadapted for insertion into standard expulsion fuse cartridges of varyinglengths and bores, said tension being predetermined when the componentparts of the link are assembled prior to insertion into said cartridge,saidfuse link comprising a fusible section, a flexible conducting leadercomposed of a relatively largel number of fine wires in parallelelectrical conducting relation, means electrically connecting thefusible section and the flexible conducting leader and comprising asection which is less readily fusible than the fusible section and theflexible conducting leader, whereby to prevent fusing of the flexibleconducting leadeg` when the fusible section has blown, a spring engagingsaid means, and spring stressing means providing a predetermined tensionforce on said fusible section when said elements are assembled forinsertion in said cartridges, at least a portion of said leaderextending to a point remote from said tending out of the other end ofsaid fuse tube for connection to the other line terminal, fusible meansinterconnecting said terminals, said conductor being freely movable-outof said fuse tube on blowing of said fusible means, and a coil springinside said fuse tube and anchored at the other end thereof and arrangedto bias said terminals apart.

30. A replaceable fuse link comprising, a fuse tube the inner surface ofwhich is provided with an arc extinguishing material which is adaptedunder the action of an arc to evolve a gaseous arc extinguishing medium,a pair of relatively infusible terminals one being located at one end ofsaid fuse tube and the other being movably mounted within said fusetube, a iiexible lead connected to the other of said terminals, fusiblemeans interconnecting said terminals, and spring means biasing saidterminals apart.

31. A replaceable fuse link comprising, a fuse tube the inner surface ofwhich is provided with an arc extinguishing material which is adaptedunder the action of an arcto evolve a gaseous arc extinguishing medium,a pair of relatively infusible terminals one being located at one end ofsaid fuse tube and the other being movably mounted within said fusetube. a flexible lead connected to the other of said terminals, fusiblemeans interconnecting said terminals, and a spring operativelyinterconnecting said fuse tube and said fusible means and placing theformer in compression and the latter in tension.

32. A renewable fuse link comprising a fuse tube, a first fuse terminalat one end of said fuse tube, a conductor including a second fuseterminal and a flexible lead extending out of the other end of said fusetube, fusible means interconnecting said fuse terminals, and a springcarried by the link and tensioning said fusible means.

33. A renewable fuse link comprising, a fuse tube, a first relativelyinusible terminal at one end of said fuse tube, a second relativelyinfusible terminal within said fuse tube, a fuse wire interconnectingsaid terminals, a flexible lead connected to said second terminal andextending out of the other end of said fuse tube, land a coil springcarried by the link and biasing said terminals apart.

34. A renewable fuse link comprising, a fuse tube, a fuse terminal atone end of said fuse tube, a iiexible lead extending out of the otherend of said fuse tube, a fusible element interconnecting said fuseterminal and said flexible lead, a spring carried by the link andtensioning said fusible element, and means securing said one end of saidfuse tube to said fuse terminal independently of said spring.

35. A fuse link comprising spaced conducting elements, a tubular membersupported by one of said elements, an insulating tube supported at leastin part by said tubular member, and a iusible element joining saidconducting elements located within said tube.

36. As an article of manufacture, a se1f-con tained fuse link comprisinga fusible element, a rst terminal for said element comprising arelatively rigid member, a tube of insulation enclosing said element andresting endwise against said rst terminal, anchor means for the remoteend of said tube, a iiexible lead having an extension passing throughsaid anchor means and forming a secondterminal for said element, and aspring connected between said anchor means and said second terminal forplacing said element under tension.

37. As an article of manufacture, a self-contained fuse link comprisinga fusible element, a first terminal for said element comprising arelatively rigid member, a tube of insulation enclosing said element andresting endwise against said rst terminal, anchor means for the remoteend of said tube, a flexible lead having an extension passing throughsaid anchor means and forming a second terminal for said elementI and aspring connected between said anchor means and said second terminal forplacing said element under tension, said rigid member having meansadaptable to clamping means of various forms for anchorage to theterminal at the closed end of a fuse tube.

38. A replaceable fuse link comprising a fuse tube, a terminal at oneend of said fuse tube, a iiexible lead extending out of the other end ofsaid fuse tube, a fusible section interconnecting said terminal and saidexible lead, a coil spring inside said fuse tube tensioning Said fusiblesection and compressing said fuse tube, and means substantiallyuniformly distributing the stress of said spring as applied incompressing said fuse tube.

39. A replaceable fuse link comprising a fuse tube, a terminal at oneend of said fuse tube, a conductor extending out of said fuse tubeincluding a terminal and a exible lead connected thereto, a fusiblesection interconnecting said terminals, a coil spring inside said fusetube tensioning said fusible section and compressing said fuse tube, andmeans substantially uniformly distributing the stress of said spring asapplied in compressing said fuse tube.

ALWIN G. STEINMAYER,

DISCLAIMER th Milwaukee, Wis. FUSE LINK CONSTRUC- 2,270,225.-Alwn G.Steinmayer, Sou

13, 1942. Disclaimer filed May 4, 1942, by

TION. Patent dated January the assignee, Line Material Company. Herebyenters this disclaimer to claims 12, 13, 14, 15, 16, 17, 18, 21, 22, 23,24, 25, and 27 to 39, inclusive, of said Letters Patent.

[Oice'al Gazette May 26, 1942.]

DISCLAIMER ilwaukee, Wis. FUsE LINK CONSTRUC- 2,270,225.-Alwn G'.Steinmayer, South M 42. Disclaimer filed May 4, 1942, by

TION. Patent dated January 13, 19 the assignee, Line Material Company.Hereby enters this disclaimer to claims 12, 13,. 14, 15, 16, 17, 18, 21,22, 23, 24, 25, and 27 to 39, inclusive, of said Letters Patent.

[Oicial Gazette May Q6', 1942.]

